diff --git a/lib/ex_doc/formatter/html/templates/head_template.eex b/lib/ex_doc/formatter/html/templates/head_template.eex
index f7b46e8bd..343289459 100644
--- a/lib/ex_doc/formatter/html/templates/head_template.eex
+++ b/lib/ex_doc/formatter/html/templates/head_template.eex
@@ -23,6 +23,7 @@
     <script src="<%= asset_rev config.output, "dist/handlebars.runtime-*.js" %>"></script>
     <script src="<%= asset_rev config.output, "dist/handlebars.templates-*.js" %>"></script>
     <script src="<%= asset_rev config.output, "dist/sidebar_items-*.js" %>"></script>
+    <script src="docs_config.js"></script>
     <script async src="<%= asset_rev config.output, "dist/html-*.js" %>"></script>
     <%# Extra content specified by the user (e.g. custom CSS) %>
     <%= before_closing_head_tag(config, :html) %>